Production of aryl indans



cal.

Patented Oct. 24, 1950 6,8

UNITED STATES PATENT OFFICE PRODUCTION or ARYL INDANS Vladimir N.Ipatieff and Herman Pines, Chicago,

Ill., assignors to Universal Oil Products Company, Chicago, 111., acorporation of Delaware No Drawing. Application November 28, 1947,Serial No. 788,644

19 Claims. (01. 260 668) 1 2 This application is a continuation-in-partof We have developed a method for producing our co-pending applicationSerial Number indan hydrocarbons by effecting a hydrogen 619,430 filedSeptember 29, 1945, now abandoned. transfer reaction between a branchedchain ole- This invention relates to a process for profinic hydrocarbonand an aromatic hydrocarbon ducing aryl indan hydrocarbons andparticularly 5 containing at least two and not more than five forproducing phenyl indan hydrocarbons and hydrocarbon substituents withtwo substituents alkylated or cycloalkylated phenyl indan hydroin paraposition. One of said para-substituents carbons. contains at least threecarbon atoms and also An object of this invention is the production hasa hydrogen atom combined with the carbon of an aryl indan hydrocarbon.atom that is joined to the aromatic ring. The Another object of thisinvention is the producreaction is illustrated by the following equationtion of an alkylated aryl indan hydrocarbon. wherein m is selected fromzero and the small A further object of this invention is the producevennumbers 2, 4, etc. tion of an alkylated phenyl indan. B

One specific embodiment of this invention relates to a process forproducing an indan hydrocarbon which comprises reacting at hydrogen20.11 transfer conditions in the presence of an acid acting catalyst abranched-chain olefin and a para-disubstituted benzene hydrocarbonhaving R2 C CH(R3R4) as one substituent a hydrocarbon group contain- H Ring only one hydrogen atom joined to the carbon atom combined with thebenzene ring. K 4) Another embodiment of this invention relates I to aprocess for producing an indan hydrocar- Tam) c 2c H2n-z+fl bon wnichcomprlses reacting 1n the presence of an acid-acting catalyst an alkylcyclohexene hydrocarbon and a para-disubstituted benzene hy- I drocarbonhaving as one substituent a group con- R taining only one hydrogen atomjoined to the 1 carbon atom combined with the benzene ring.

A further embodiment of this invention relates to a process forproducing aryl indan hydrocarbons which comprises reacting at hydrogentransfer conditions in the presence of an acid- Similarly the productionof 1,3,3,6-tetramethyl-1-ptolylindan from p-cymene and Z-methyl-Z-butene is indicated by the equation:

acting catalyst an alkylcyclohexene hydrocarbon CH3 and a benzenehydrocarbon of the formula CH 3 2 2CH3&=CHCH3 R.-

CH3( JHCH3 p- Cymene 2-methyl-2-butene R4R (EH3 t CGHa wherein R1 isselected from the group consisting I E of a hydrogen atom, an alkylradical, a cycloalk- \/\(|3 Q H0HrCH3 alkyl radical, and a cycloalkylradical, and H each of R2, R3 and R4 is selected from the groupconsisting of an alkyl radical, a cycloalkalkyl radical, and acycloalkyl radical. By the term cycloall'zalkyl is meant a hydrocarbonradical in which a cycloalkyl group replaces a hydrogen CH3 atom of analkyl group. A cycloalkalkyl radical 1,3,3,fii-tetramethyl-l-p-tolylindan iso-pentane is thus a cycloalkyl derivative of an alkyl radi- Theformation of 1,3,23,6-tetramethy1-1-ptolylindan by hydrogen transferbetween pcymene and a methylcyclohexene is illustrated by the followingequation:

(1H3 CH3 CH2 l CH3CH-CH3 p-Cymcne Methylcyclo- Methylcyclohexene-Bhexane (1H3 CCH:

CH2 H3O 1,3,3,6-tetramethyl-l-p-tolylindau Hydrogen transfer betweenZA-diisopropyltoluene and a branched chain olefin such asmethylcyclohexene proceeds according to the equation:

l,3,3,(l-tetrnmethyl-5-isopropyl-l-(4 n1ethyl-3-isopropyl-phenyl)indanAlso hydrogen transfer between 4-isopropyli 2-cyclohexyltoluene andmethylcyclohexene takes place to yield the products indicated by thefollowing equation:

| CH;CH-CH3 4-isopropyl-2- Methylcyclo- Methylcyclocyclohexyltolucnehexene hexane CH; Q m

CH: 1130 c l\ 1,3,3,b-tetram ethyl-5-oyclohexyl-1- (4-methyl-S-cyclohexylphenyl) indan In the cycloalkylated phenylindanhydrocarbons so formed, the cycloalkyl groups may consist of eithermonocyclic or polycyclic saturated groups having the general formulacnHzn-i, CnHZn-Ii, etc. The cycloalkyl group may be attached directly tothe aromatic nucleus or it may be attached through an alkylene group asCH2, CH2CH2, etc. The cycloalkyl group may also consist of fused rings.

The aromatic compound used in this synthesis of an indan contains atleast one para-arrangement of hydrocarbon group substituents in order totake part in this hydrogen transfer reaction. Also one of thesubstituents in the para-arrangement must have only one hydrogen atomcombined with the carbon atom attached to the benzene ring. Accordingly,this hydrocarbon substituent which contains the tertiary hydrogen atomalso contains at least three carbon atoms.

Such aromatic hydrocarbons which are useful as starting material for theprocess have the structures represented by the formula:

wherein R, represents a member selected from the group consisting of ahydrogen atom, an alkyl radical, a cycloalkalkyl radical, and acycloalkyl radical, and each of R2, R3 and R4 is selected from the groupconsisting of an alkyl radical, a cycloalkalkyl radical, a cycloalkylradical, and a bicycloalkyl radical. The combination of the different R.groups should be balanced so as to avoid steric hindrance. Also aromatichydrocarbons and particularly benzene hydrocarbons containing more thanthree hydrocarbon substituent groups may also be present in a startingmaterial provided that such a hydrocarbon has a replaceable hydrogenatom combined with a nuclear carbon atom adjacent to the carbon atomwhich is combined with the group:

Such aromatic starting materials include p-cymene,1,2-dimethy1-4-isopropyl benzene, 2,4-diisopropyl toluene,4-isopropyl-2-cyclohexy1 toluene, etc.

Olefinic starting materials suitable for this hydrogen transfer processhave branched chains and include such hydrocarbons as trimethylethylene,dihydrolimonene, methyl cyclohexene, 1,1,3-trimethylcyclohexene,menthene, etc. The exact type of olefin to be used is dependent on thecatalyst and the aromatic hydrocarbon with which the hydrogen transferis to be effected. Thus n-octene and cyclohexene, namely, olefins notpossessing branched chains, when reacted with a para-dialkyl aromatic atoperating conditions similar to those used with the branched chainolefins, effect alkylation but not hydrogen transfer.

In addition to the branched chain monoolefins mentioned above, otherolefin-acting compounds which are also utilizable in this processcomprise conjugated diolefins containing a tertiary carbon atom,alcohols, ethers, esters of carboxylic acids,

and alkyl halides which may be regarded as capable of forming branchedchain olefins in situ in the reaction mixture.

The process as herein described is carried out in the presence of anacid-acting catalyst at conditions necessary for the hydrogen transferreaction. Suitable acid-acting catalysts include mineral acids, such assulfuric acid, chlorosulfonic acid, fluorosulfonic acid, hydrogenfluoride, hydroxyborofiuoric acids, fluorophosphoric acids, phosphoricacids; Friedel-Crafts halide catalysts, particularly aluminum chloride,aluminum bromide, ferric chloride, zirconium chloride, boron fluoride.Since in some cases Friedel-Crafts catalysts may cause an alkylmigration within the aromatic ring before the hydrogen transfer reactionoccurs, it is sometimes advantageous to use Friedel-Crafts complexes,such as etherate, alcoholate, etc. for this reaction.

Phosphoric acid catalyst comprise orthophosphoric acid and alsopolyphosphoric acids such as pyrophosphoric acid, triphosphoric acid,and tetraphosphoric acid. Under certain conditions of operation variousacid-acting oxide-type catalysts may be used which include activatedclays, silica-alumina composites, and other silica-containing materialswhich are generally utilizable as catalysts for hydrocarbon cracking.

The operating conditions used in the process are dependent upon thenature of the hydrocarbons being treated and also upon the catalystsemployed. When utilizing strong mineral acids, such as hydrogenfluoride, sulfuric acid, fluorosulfonic acid, chlorosulfonic acid, andthe like, and also Friedel-Crafts metal halides promoted by a hydrogenhalide such as hydrogen chloride, the process is carried out at atemperature of from about 30 to about 100 C., and at a pressure up toabout 100 atmospheres. However, in the presence of hydrogen fluoride,sulfuric acid, and aluminum chloride catalysts the preferred operatingtemperature is generally from about 0 to about 50 C., While in contactwith ferric chloride catalyst the preferred operating temperature isfrom about 50 to about 100 C. Silicaalumina and other synthetic oxidecatalysts and k clays are generally used at a temperature of from about200 to about 400 C. and at a superatmospheric pressure generally not inexcess of about 100 atmospheres.

Our process is carried out in either batch or continuous type ofoperation. In batch type operation the usual procedure consists inplacing a mineral acid or Friedel-Crafts catalyst and a portion,generally about 50%, of the aromatic hydrocarbon in a reactor providedwith a mechanically driven stirrer, cooling these materials to atemperature of from about 0 to about C. and adding thereto withstirring, a solution of the olefin in the remainder of the aromatichydrocarbon.

The reaction mixture is then separated and the product is washed, dried,and distilled to separate therefrom the indan hydrocarbons. Unconvertedaromatic hydrocarbons recovered in this distillation are utilizable inthe further operation of the process.

The process is also carried out in a continuous manner by passing thearomatic and cycloolefinic hydrocarbons through a suitable reactor inwhich they are contacted in the presence of the catalyst, the lattereither as a liquid or as a solid, depending upon the catalyst employedin the process. When using mineralacid catalysts such as sulfuric acid,chlorosulfonic acid, or hydrogen fluoride, this catalytic material isintroduced continuously to the reactorwhich is provided with 6 suitablemixing means and the resultant product is then separated into ahydrocarbon layer and a catalyst layer, the latter being returned tofurther use in the process while the hydrocarbon layer is washed, dried,and distilled as hereinabove set forth. When a solid catalyst such assilica-alumina, clay, or a supported Friedel- Crafts type catalyst isused as a fixed bed in the reactor and the aromatic and cycloolefinichydrocarbons are passed therethrough, the resultant hydrocarbon productrequires no washing and drying treatment and. may be separated bydistillation to separate therefrom unconverted aromatic andcycloolefinic hydrocarbons and to recover the desired indanhydrocarbons.

In order to obtain relatively high yields of indan hydrocarbons by ourprocess, it is necessary to use rather carefully selected hydrocarbonfractions as charging stocks. As already indicated herein, only certaintypes of aromatic hydrocarbons, namely those containing particularsubstituents are utilizable as starting materials to produce indan-typehydrocarbons. Thus isopropyltoluene, secondary butyl toluene, paradiisopropylbenzene and others react readily with branched chain olefinsto form anindan hydrocarbon and a saturated hydrocarbon, the latterhaving substantially the same carbon skeleton as that of the olefinichydrocarbon charged to the process. An aromatic hydrocarbon which doesnot contain the aforementioned disubstitution in para position does notreact with a branched chain olefin to give the desired hydrogen transferreaction. Also an olefin which does not have a branched chain such as ispresent in trimethylethylene, dihydrolimonene, methylcyclopentene, etc.acts as an alkylating agent for the aromatic hydrocarbon also charged tothe process. Accordingly, in order to obtain hydrogen transfer ratherthan alkylation it is necessary to use a branched chain olefinichydrocarbon together with a disubstituted benzene hydrocarbon in whichthe substituents are in para position and one of said substituentscomprises an isopropyl group or other hydrocarbon group in which atertiary hydrogen is combined with the carbon atom adjacent to thearomatic nucleus.

The indans formed in this process may be sulfonated and hydrolyzed toform phenols or they may be nitrated and reduced to the correspondingamine. The amine may then be diazotized and converted into phenols whichmay be useful as inhibitors. The sulfonation product of an indancontaining a long alkyl, cycloalkalkyl or cycloalkyl group may also beconverted into a detergent. Some of the indan hydrocarbons formed in theprocess are also useful as additives in lubricating oils.

The following examples are given to illustrate the character of resultsobtained by the use of specific embodiments of the present invention,although the data presented are not introduced with the intention ofunduly restricting the generally broad scope of the invention.

Example I 33.5 grams (0.25 mole) of para-cymene and grams of sulfuricacid of 96% concentration were placed in a glass reactor provided with amechanically driven stirrer. The mixture of sulfuric acid andpara-cymene was maintained at a temperature of 0 to 10 C. by an ice bathsurrounding the reactor and then a mixture of 34 grams (0.25 mole) ofmenthene and 33.5 grams of paracymene (0.25 mole) was added to thereactor with,

hydrogen,

stirring during a period of about 1 hour and then the stirring wascontinued for an additional 0.5 hour. At the end of this time thehydrocarbon layer was separated from the catalyst layer and the formerwas washed, dried, and distilled. In addition to 47 grams (0.35 mole) ofunconverted para-cymene which was recovered, there was obtained 20 grams(0.14 mole) of saturated hydrocarbons comprising essentially menthaneand 7.8 grams (0.06 mole) of 1,3,3,6-tetramethyl-1-ptolylindan.

Emample II 53.5 grams (0.4 mole) of para-cymene and 67 grams ofsubstantially anhydrous hydrogen fluoride were placed in a copper-linedreactor provided with a mechanically driven copper stirrer and thereaction mixture was cooled to a temperature of to about 10 C. Thecooled reaction mixture was then stirred while a mixture of 53.5 grams(0.4 mole) of para-cymene and 55 grams (0.4 mole) of dihydrolimonene wasadded thereto during a period of 1 hour and the stirring was continuedfor 0.5 hour. The catalyst layer was then separated from the hydrocarbonlayer and the latter was washed, dried, and distilled. 59 grams (0.44mole) of para-cymene was recovered, thus indicating that 0.36 mole ofpara-cymene had entered the reaction. The hydrocarbon product contained40 grams (0.29 mole) of saturated hydrocarbons comprising essentiallypara-methylisopropylcyclohexane and 41 grams (0.15 mole) of1,3,3,6-tetramethyl-l-p-tolylindan.

Another run at essentially the same conditions yielded 149 grams ofhydrocarbon material which was separated by distillation into thefollowing fractions:

By ultraviolet absorption analysis, Fraction 1 contained 77% ofp-cymene. Accordingly, Fraction 1 was treated at 0 C. with sulfuric acidcontaining 15% of sulfur trioxide in order to remove p-cymene. Afterthree such treatments, 19 grams of saturated hydrocarbon material wasobtained boiling at 160 having a refractive index n of 1.4380 andcorresponding to p-menthane, which yielded p-cymene on dehydrogenationin the presence of platinized alumina at 240 C.

Fraction 5 with a boiling point of 328-330 C. at 760 mm. pressurecorresponded to 1,3,3,6-tetramethyl-l-p-tolylindan, and by analysiscontained 91.31% by weight of carbon and 8.96% of It yielded atetranitro compound melting at 249 C., the same as that of thetetranitro derivative of synthetically prepared 1,3,3,6-tetramethyl-1-p-toly1indan.

Example III Following the procedure of Example I, 134 grams ofpara-cymene (1.0 mole), 48 grams of l-methylcyclohexene (0.5 mole) and61 grams of sulfuric acid of 96% concentration were contacted in a glassreactor at 0 to C. for 1 hour. From the resultant reaction product therewas obtained 88 grams (0.66 mole) of unconverted I 7 Boiling PointRefractive Wei ht Fraction Number Index, G g 7mm] rams C. at mm.

101 700 1. 4220 114 -172 700 1. 4788 9 172-174 700 1. 4890 378 40-101 1.50 0 101-124 1. 8 124-120 1. 23 -138 1. S 138-150 1. 5 150 1. 123Ab0vcl56 8 Investigation of these fractions showed that Fraction 1consisted of methylcyclohexane, Fraction 3 consisted of unreactedpara-cymene, Fraction 6' corresponded to methylcyclohexyl-p-cymene andFraction 9 corresponded to 1,33,6- tetramethyl-l-p-tolylindan, which onnitration yielded 1,3,3,6-tetramethyl-5-nitro-l-(4-methyl-3-nitrophenyl) -indan melting at 1121l4 C. and 1,3,3,6 tetramethyl 5,7dinitro 1-(4-methyl- 3,5-dim'trophenyl) -indan, melting at 251-252 C.

Example IV By utilizing the procedure of Example II, 107 grams (0.8mole) of para-cymene, 38.4 grams of l-methylcyclohexene (0.4 mole) and67 grams of liquid hydrogen fluoride were contacted at 0 to 10 C. for 1hour. The resultant reaction mixture contained 54 grams (0.4 mole) ofunconverted para-cymene, thus indicating that 0.4 mole of thishydrocarbon had undergone reaction. The reaction mixture also contained28 grams (0.28 mole) of saturated hydrocarbons comprising essentiallymethylcyclohexane and 32 grams (0.12 mole) of1,3,3,6-tetramethyl-1-p-tolylindan.

Repetition of this run on a larger scale yielded 675 grams ofhydrocarbon reaction product which was distilled and separated intofractions shown in the following table:

Bmhng Pomt Refractive Wei ht Fraction Number Index, G g 71 D20 rams C.at mm.

Above 3 0. 5

These various fractions of hydrocarbon material were stable to dilutepotassium permanganate solution, thus indicating the absence of olefinichydrocarbons. Investigation of the various fractions showed thatFraction 1 consisted of methylcyclohexane, Fraction 3 was unreactedp-cymene, Fraction 6 (boiling point 290-293 at 760 mm.) corresponded tomethylcyclohexyl-p-cymene, and

9 Fraction 9 (boiling point 318-326 C. at 760 mm.) which melted at37.5-38 C. corresponded according to the physical constants, ultravioletabsorption analysis, and nitro derivative of1,3,3,6-tetramethyl-l-p-tolylindan.

Example V By employing the apparatus and procedure of Example I, 64grams (0.43 mole) of para-cymene and 33.5 grams (0.27 mole) of1,1,3-trimethy1cycylohexene were reacted in the presence of 58 grams of96% sulfuric acid at to C. The resultant reaction mixture contained 39grams (0.29 mole) of para-cymene, thus indicating that 0.19 mole ofpara-cymene had reacted. The reaction mixture also contained 18 grams(0.14 mole) of saturated hydrocarbons comprising essentially1,1,3-trimethylcyclohexane and 18 grams (0.07 mole) of1,3,3,6-tetramethy1-1-p-tolylindan.

Example VI Following the procedure of Example II, 87 grams (0.64 mole)of para-cymene and 39.8 grams (0.32 mole) of 1,1,3-trimethylcyclohexenewere reacted at 0 to 10 C. in a copper-lined reactor in the presence of55 grams of substantially anhydrous hydrogen fluoride. The resultantreaction mixture contained 49 grams (0.37 mole) of unconvertedpara-cymene thus indicating that 0.27 mole of para-cymene reacted. Thereaction mixture also contained 31 grams (0.25 mole) of saturatedhydrocarbons comprising essentially 1,1,3-trimethylcycloheXane and 30grams (0.12 mole) of 1,3,3,6tetramethyl-l-p-tolylindan.

Example VII 168 grams of anhydrous hydrogen fluoride and 134 grams ofpara-cymene were introduced into a copper flask provided with a copperstirrer and dropping funnel, said flask being surrounded by a coolingbath of ice and water. 70 grams of trimethylene and 134 grams ofpara-cymene were mixed and the mixture was then added slowly withstirring to hydrogenfiuoride-para-cymene mixture contained in the copperflask. Usually from 1 to 3 hours were required to complete the action ofthe trimethylethylene-paracymene mixture after which the stirring of thereaction mixture was continued for an additional time of 30 minutes, andthen the content of the flask was poured into a copper beaker containingice pre-cooled to about 30 C. The resultant hydrocarbon material wasseparated, washed with dilute aqueous potassium hydroxide solution, thenwashed with water. dried over anhydrous calcium chloride and distilled.A total of 308 grams of a hydrocarbon product was charged to such adistillation and separated into the following fractions:

Boiling Refractive Weight, Fraction Number Point, C. Index, my Grams28-30 1. 3540 21. 4 30-165 1.4488 7. 1 165-172 1. 4770 44. 0 172-17 3 1.4891 118 Above 173 117 5) were redistilled at subatmospheric pressure.The following fractions were collected:

Boiling Point Refmch-ve Fraction Number Index, $2522 C. at mm.

v-1 40-70 3. 5 1. 4003 s. 5 v-2 70-37 3. 5 1. 4040 5. 0 30-04 4. 0 1.4933 10. 5 04-05 4. 0 1. 5021 12. 5 -130 3. 0 1. 5050 0.0 -147 3. 51.5255 ll. 0 144- 3. 0 l. 5433 4. 2 144-145 3. 0 1. 5571 5. 5 Above 3.0 1. 5520 8.0

Fraction V-4 corresponded to ampyl-p-cymene. Fraction V-6 consisted of amixture of diamyl-p-cymene and 1,3,3,6-tetramethyl-1-ptolylindan.Fractions V-8 and V-9 also consisted of 1,3,3,6-tetramethyl 1 ptolylindan In this reaction between 2,4-diisopropyltoluene andmethylcyclohexene in the presence of hydrogen fluoride, the apparatusconsisted of a 250 ml. copper flask provided with a stirrer, a droppingfunnel and a thermocouple well. Twentyfive grams of hydrogen fluorideand 36 g. (0.2 M) of diisopropyltoluene, B. P. 80-82 C. at 7 mm. wereplaced in the flask. The mixture was stirred and to it was added, over aperiod of half an hour, 10 grams (0.1 M) of methylcyclohexene. Thelatter was prepared by the dehydration of 4-methylcyclohexanol overactivated alumina at 350 C. The temperature of the reaction wasmaintained at 3-10" C.; the contents of the flask was poured over icepre-cooled to --60 C. The hydrocarbon layer was separated, washed withdilute potassium hydroxide, followed by Water wash and dried overcalcium chloride. The product did not contain any organic fluorides; itwas stable towards a 2% aqueous potassium permanganate solution,indicating the absence of oleflnic hydrocarbons. Thirty-eight grams ofthe product was submitted to a distillation and separated into fractionsshown in the following table: 4

BoilingPoint R I efl'lCtlVE. Fraction Number Index, X3 313 G. atmm.19-101 760 1. 4241 6. 2 97-104 42 1. 4943 15. 0 104-117 43 1. 4980 2. 8117-125 40 1. 5028 1. 1 5 125-147 13 1. 5171 1 5 Residue l. 5397 14. 0

Fraction 1 corresponded to methylcyclohexane. On dehydrogenation, ityielded toluene. Fraction 2 was recovered diisopropyltoluene. Fraction 5was not investigated but according to physical constants it correspondsto a product resulting from the interaction of diisopropyltoluene withmethylcyclohexene.

Fraction '7 was rubbed with a small amount of methanol, the methanol wasdecanted, and the sticky product which remained was crystallized fromabsolute alcohol to which was added small quantity of acetone. Crystalswere obtained, which softened at 75 and melted'at 76. Onrecrystallizationfrom absolute alcohol, the product melted at 795 C. Theyield of the crystalline hydrocarbon amounted to 60%;of

Fraction 7. This hydrocarbon had an analysis corresponding to theformula CzcHas and consisted of 13,3,6-tetramethyl-5-isopropyl-l-(4-methyl-3-isopropylphenyl) -indan.

' Analysis: Calcd. for CzsHss: C, 89.65; H, 10.35. Found: C, 89.55; H,10.23.

One gram of the crystalline hydrocarbon was dissolved in 5 ml. ofchloroform. The solution was cooled to and to it was added 1.5 ml. of96% sulfuric acid and 0.5 m1. of 72% nitric acid; the latter was addedin three portions. The temperature was then raised to 20. A crystallinenitroderivative was obtained, melting at 238- 240. Afterrecrystallization from a solution of ethanol and chloroform, it meltedat 250; the melting point was not depressed when mixed with a knownsample of 1,3,3,6-tetramethyl--nitro- 1- (4-methyl-3-nitrophenyl)-indan.

Example IX Boiling Point Refractive Weight Fraction Number Index, G

0 7mm rams C. at mm.

760 4. 2 1.5179 29. 2 1.5220 1. 4 2 l. 5330 5. Residue ll.

Fraction 1 was completely saturated, corresponds to methylcyclohexane.Fraction 2 corresponds to unreacted cyclohexyl-p-cymene. The residueboiling above 184 C. at 2 mm. was distilled from a Claisen flask, and7.4 grams of a glass-like product boiling at 270 C. at 4 mm. wasobtained which hardened on cooling. The glasslike product when powderedmelted at 52-53. Unsuccessful attempts were made to recrystallize itfrom various solvents.

Analysis: Calcd. for (332E442 C, 89.71; H, 10.29. Found: C, 89.10; H,10.63.

Nitration of some of this powdered product was carried out in chloroformsolution as described above. A solid was obtained melting at l50153 C.After two crystallizations from ethanol-chloroform solution the meltingpoint of the nitroderivative was 162163. This melting point correspondsto that of 1,3,3,6-tetramethy1-5-nitro- 1-(4-methyl-3-cycloheXyl-5-nitrophenyl) -indan.

Analysis: Calcd. for C26H33N204! C, 70.39; H, 7.55; N, 6.40. Found: C,70.68; H, 7.37; N, 6.50.

Also this solid hydrocarbon was nitrated by treatment with a solutionconsisting of 2 vol. of 96% sulfuric acid and 1 vol. of 72% nitric acid.A tetranitro derivative was obtained melting at 251-252 which wasidentical with the melting point of 1,3,3,6-tetramethyl 5,7dinitro-l-(4- methyl-3,5-dinitro-phenyl) -indan.

Analysis: Calcd. for C30H20N4O3Z C, 54.05; H, 4.50; N, 12.61. Found: C,54.69; H, 4.71; N.12.31.

Accordingly, the hydrocarbon material of Fraction 5 consisted of1,3,3,6-tetramethyl-5-cycloe hexyl-l- (4-methyl-3-cyclohexylpheny1)-indan.

12 Example X By using the apparatus and procedure of Example V'DI, 132grams of p-cymene and 66 grams of 2,6-dimethyl-bicyclo(3,2,1) -2-octenewere reacted at 0 C. for one hour in the presence of 46 grams ofanhydrous hydrogen fluoride. The resultant hydrocarbon mixture Wasseparated from the hydrogen fluoride catalyst and then 185 grams of theformer was fractionally distilled. This distillation separated 133 gramsof a mixture of 25% 2,6-dimethyl-bicyclo(3,2,1) -2octane and 75%unconverted p-cymene from higher boiling material found to contain 30grams of 1,3,3,6- tetramethyl-l-ptolylindan and 20 grams ofbicycloalkylated p-cymene.

We claim as our invention:

1. A process for producing an indan hydrocarbon which comprises reactingat hydrogen transfer conditions in the presence of an acid-actingcatalyst a branched-chain olefin-acting compound and apara-disubstituted benzene hydrocarbon having as one substituent asaturated hydrocarbon group containing at least three carbon atoms andonly one hydrogen atom joined to the carbon atom combined with thebenzene ring.

2. A process for producing an indan hydrocarbon which comprises reactingat hydrogen transfer conditions in the presence of an acid-actingcatalyst a branched-chain oleflne and a paradisubstituted benzenehydrocarbon having as one substituent a saturated hydrocarbon groupcontaining at least three carbon atoms and only one hydrogen atom joinedto the carbon atom combined with the benzene ring.

3. A process for producing an indan hydrocarbon which comprises reactingin the presence of an acid-acting catalyst an alkyl cyclohexenehydrocarbon and a para-disubstituted benzene hydrocarbon having as onesubstituent a saturated hydrocarbon group containing at least threecarbon atoms and only one hydrogen atom joined to the carbon atomcombined with the benzene ring.

4. A process for producing an aryl indan hydrocarbon which comprisesreacting at hydrogen transfer conditions in the presence of anacidacting catalyst an alkylcyclohexene hydrocarbon and a benzenehydrocarbon of the formula wherein R1 is selected from the groupconsisting of a hydrogen atom, an alkyl radical, a cycloalkalkylradical, and a cycloalkyl radical, and each of R2, R3 and R4 is selectedfrom the group consisting of an alkyl radical, a cycloalkalkyl radical,a cycloalkyl radical, and a bicyclo-alkyl radical.

5. A process for producing an indan hydrocarbon which comprise reactingin the presence of a mineral acid catalyst at a temperature of fromabout -30 to about C., a branched chain olefin and a para-disubstitutedbenzene hydrocarbon having as one substituent a saturated hydrocarbongroup containing at least three carbon atoms and having a hydrogen atomjoined to the carbon atOm combined with the benzene ring.

6. A process for producing an indan hydrocarbon which comprises reactingin the presence of a mineral acid catalyst at a temperature of fromabout -30 to about 100 C. a branched chain alkene and apara-disubstituted benzene hydrocarbon having as one substituent asaturated hydrocarbon group containing at least three carbon atoms andhaving a hydrogen atom joined to the carbon atom combined with thebenzene ring.

7. A process for producing an indanhydrocarbon which comprises reactingin the presence of a mineral acid catalyst at a temperature of fromabout 30 to about 100 C. an alkyl cyclo-olefin and a para-disubstitutedbenzene hydrocarbon having as one substituent a saturated hydrocarbongroup containing at least three carbon atoms and having a hydrogen atomjoined to the carbon atom combined with. the benzene ring.

8. A process for producing an indan hydrocarbon which comprises reactingin the presence of a sulfuric acid catalyst at a temperature of fromabout to about 50 C. a branched-chain olefin and a para-disubstitutedbenzene hydrocarbon having as one substituent a saturated hydrocarbongroup containing at least three carbon atoms and having a hydrogen atomjoined to the carbon atom combined with the benzene ring.

9. A process for producing an indan hydrocarbon which comprises reactingin the presence of a hydrogen fluoride catalyst at a temperature of fromabout 0 to about 50 C. a branched-chain olefin and a para-disubstitutedbenzene hydrocarbon having as one substituent a saturated hydrocarbongroup containing at least three carbon atoms and having a hydrogen atomjoined to the carbon atom combined with the benzene ring.

10. -A process for producing an indan hydrocarbon which comprisesreacting in the presence of a hydrogen fluoride catalyst at atemperature of from about 0 to about 50 C. a branched-chain alkene and apara-disubstituted benzene hydrocarbon having as one substituent asaturated hydrocarbon group containing at least three carbon atoms andhaving a hydrogen atom joined to the carbon atom combined with thebenzene ring.

11. A process for producing an indan hydrocarbon which comprisesreacting in the presence of a hydrogen fluoride catalyst at atemperature of from about 0 to about C. an alkyl cycloolefin and apara-disubstituted benzene hydrocarbon having as one substituent asaturated 1'4 hydrocarbon group containing at least three carbon atomsand having a hydrogen atom joined to the carbon atom combined with thebenzene Ill'lg.

12. A process for producing 1,3,3,6-tetramethyll-p-tolylindan whichcomprises reacting a branched-chain olefin and. para-cymene in thepresence of an acid-acting catalyst at hydrogen transfer conditions.

13. A process for producing 1,3,3,6-tetramethyll-p-tolylindan whichcomprises reacting a branched-chain olefin and para-c'ymene in thepresence of a mineral acid catalyst at a temperature of from about -30to about C.

14. A process for producing 1,3,3,6-tetramethyll-p-tolylindan whichcomprises reacting a branched-chain olefin and para-cymene in thepresence of a sulfuric acid catalyst at a temperature of from about 0 toabout 50 C.

15. A process for producing 1,3,3,6-tetramethyll-p-tolylindan whichcomprises reacting a branched-chain olefin and para-cymene in thepresence of a hydrogen fluoride catalyst at a temperature of from about0 to about 50 C. o

16. A process for producing 1,3,3,6-tetramethy1- 5-isopropyl-1-(4-*nethy1-3-isopropy1phenyl) -indan which comprises reactingdiisopropyltoluene and methylcyclohexen'e in the presence of a hydrogenfluoride catalyst at a temperature of from about 0 to about 50 C.

17. A process for producing 1,3,3,6-tetramethyl- 5- cyclohexy1-1-(4-methyl-3-cyclohexylphenyl) indan which comprises reacting4-methyl-2-cyc1ohexyltoluene and methylcyclohexene in the presence ofhydrogen fluoride catalyst at a temperature of from about 0 to about 50C.

18. An aryl indan having acycloalkyl group combined with each of twoaromatic rings.

19. 1,3,3,6 tetramethyl 5cyclohexyl-l-Ulmethyl-3-cyclohexylphenyl-indan.

VLADIMIR N. IPATIEFF. HERMAN PINES.

REFERENCES CITED The followingv references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Thomas Sept. 7, 1943 OTHER REFERENCESNumber

1. A PROCESS FOR PRODUCING AN INDAN HYDROCARBON WHICH COMPRISES REACTING AT HYDROGEN TRANSFER CONDITIONS IN THE PRESENCE OF AN ACID-ACTING CATALYST A BRANCHED-CHAIN OLEFIN-ACTING COMPOUND AND A PARA-DISUBSTITUTED BENZENE HYDROCARBON HAVING AS ONE SUBSTITUENT A SATURATED HYDROCARBON GROUP CONTAINING AT LEAST THREE CARBON ATOMS AND ONLY ONE HYDROGEN ATOM JOINED TO THE CARBON ATOM COMBINED WITH THE BENZENE RING. 